Manufacture of tobacco sheet



Dec. 12, 1961 w. A. DRUCKER 3,012,561

MANUFACTURE OF TOBACCO SHEET Filed June 12, 1957 GRIND HEAT TOBACCOPLASTIC FILM APPLY TOBACCO T0 HOT PLASTIC FILM PRESS TOBACCO INTO FILMHARDEN FILM OR CURE POLYMER BRUSH OFF LOOSE TOBACCO CUT SHEET T0 SIZEINVENTOR WILLIAM A. DRUCKER' ATTORNEY United States Patent O 3,012,561MANUFACTURE OF TOBACCO SHEET William A. Drucker, New York, N.Y.,assignor to American Machine & Foundry Company, a corporation of NewJersey Filed June 12, 1957, Ser. No. 665,188 11 Claims. (Cl. 131-140)This invention relates to the manufacture of tobacco sheet. Inparticular the invention concerns the combiation of finely dividedtobacco imbedded in thermoplastic film.

Many proposals have been made for the manufacture of tobacco sheet fromfinely divided tobacco. All of these methods require the treatment ofadhesive material with a solvent or liquid dispersing material (such aswater) which is removed from the sheet by final evaporation.

Heretofore, all methods of forming tobacco sheet by the application oftobacco material to a sticky film have relied upon the support of thefilm either upon the surface of rollers or on a belt at the time tobaccois applied to the film. This has generally been done because the filmlacks enough tensile strength to be self-supporting prior to drying orbecause a sticky liquid coating on a solid base, such as paper, isinclined to fiow' off unless the base is supported horizontally on alarge surface. In

all cases drying the sheet has been a necessary operation. Coating hasbeen limited to a sequential operation rather than coating both sides ofa sticky carrier layer at once.

a method of forming tobacco sheet from a thermally softened adhesive.

It is also an object of the invention to provide a method of formingtobacco sheet by applying finely divided tobacco to a suspendedself-supporting sticky film.

Another object of the invention is to provide a tobacco sheet whichincludes finely divided tobacco and thermally softened adhesivematerial.

A further object of the invention is to provide a method of formingtobacco sheet by applying tobacco powder to a suspended thermallysoftened film.

These and other objects are described more particularly in the followingaccount of the invention taken together with the accompanying drawingwhich shows a box type flow diagram of a method of making tobacco sheetaccording to the invention.

According to a preferred form of the invention as shown in the drawing,adhesive material such as selfsupporting thermoplastic film is formedand fused by heat into a sticky sheet. This may be done by extrusion ofthe plastic as between heated sheeting rollers or through a heated die.Radiant heat may also soften the film. The adhesive film may containadmixed fiber and/or tobacco material. The film is preferably madesticky by heating.

The film is preferably suspended either vertically or horizontally. Thefact that it is strong and coherent enough to be suspended indicatesthat it is self-supporting. In a preferred form of the invention thesuspension is vertical, and the film hangs from the nip or bite ofsheeting rollers, which may be heated.

The advantage of suspending a film so that both surfaces are exposed isutilized by the simultaneous application of tobacco material to thesesurfaces, although simple application of tobacco to only one surface isalso within the scope of the invention.

The sticky film can be moved when in vertical disposition in either anupward or downward direction past a tobacco application station. Thesheet may also be suspended horizontally or at any angle between thevertical Therefore, it is an object of this invention to provide3,012,561 Patented Dec. 12, 1961 and the horizontal at the time tobaccomaterial is applied to the surface.

Tobacco may be applied by impinging upon the film a current of dustladen hot gas or the film may be moved through a loosely packed hopperof tobacco material which may be heated. The material in the hopper ispreferably in dust or powder form but may also be in paste form. Hotrollers or presses are valuable forcombining the tobacco and theadhesive matrix.

The tobacco is preferably dry ground. All parts of the tobacco plant maybe used. Various kinds of tobacco may be blended. However, tobaccoextracts may also be used in combination with other non-tobacco materialto form a tobacco type material.

Generally a very thin sheet is formed. A sheet between one and ten milsis usual but about four mils is preferable. Strength is at least that ofleaf tobacco although often much greater, and tobacco content may rangehigher than The adhesive may be cured and hardened, as by an includedcatalyst, or refrigeration. The. sheet isthen preferably brushedfree ofloose particles and cut to size.

The sheet is suitable for use in smoking articles such as cigarsandcigarettes either as a shredded filler or as a wrapping sheet. l

The preferred adhesive for use with tobacco in this invention is ethylcellulose film. Various cellulose base esters and others and mixturesand copolymers thereof, which may be conventionally plasticized, areequally suitable. They include acetate, propionate and butyrate ofcellulose.

Alkyl cellulose ethers such as ethyl cellulose are particularly suitablewhen 50 or more of the hydroxyl radicals of cellulose have been replacedby alkoxy groups.

'Non-ecllulosic thermoplastic polymers such as olefins of thepolyethylene type and polyamides of the nylon type as well as vinyl andvinylidene resins such as polyvinyl alcohol are also suitable.

Although some of the non-cellulosic materials burn poorly, theyare usedin such relatively small amounts and may be combined with conventionalburn catalysts so that. the sheet will, nevertheless, burn well andundesirable odor be masked by the preponderant quantity of tobacco whichis preferably over 90% by weight.

The following examples illustrate the invention in a preferred form:

Example I A sheet of ethyl cellulose about one-half mil thick,plasticized by an approximately one-third content of ethylene glycol,Was heated to about 200 C. with radiant heaters to make it very soft andsticky. The hot sheet was suspended and coated with -80 mesh tobaccodust which had preferably been heated to about C. The dust was pressedinto the sheet with heated rollers until the sheet was nearly saturatedwith tobacco. The plastic was cooled by cold air and cold rollers, andthe surface was brushed to remove loose particles. The sheet was thenslit to a convenient width and wound onto a core. This method is shownin the drawing. This sheet contined about 92% of tobacco material. Thestrength was in excess of 250 grams per inch Width and extensibility wasgood. Sheet weight was about 2.13 grams per square foot.

Example I1 Another method of forming tobacco sheet from thermoplasticfilm is illustrated in the batch process of clamping a sheet of 1.5 milolyethylene film covered on both sides with a layer of -80 mesh tobaccopowder between stifli metal or glass plates and heating the sandwich inan oven at about C. for five minutes. The sheet was removed from theoven and brushed to remove loose dust. This sheet was about 75% tobaccoand had a uniform tobacco appearance. The burn odor had some wax orparafin smell but was suitably masked by blending with leaf tobacco andflavoring material.

The invention also contemplates broadly the technique of suspending asticky sheet to which tobacco is applied, and this aspect of theinvention is not strictly limited to heat softened plastics, butincludes the treatment of any sheet of good burn character by theapplication of tobacco while the sheet is suspended. Adhesive may bemixed with the tobacco. Such a sheet may even be a tobacco sheetmaterial, and the material applied thereto while the sheet is suspendedmay be merely a tobacco extract as well as a dust. The principal featureof this part of the invention is the suspension of the film.

A sheet or portion of a sheet is deemed to be suspended according tothis invention when it is supported at one or more edges with the fiatsurfaces of the sheet free from support. This is distinct from sheetlaid upon a forming surface, such as a belt, plate or screen.

Broadly stated this invention involves two features both separately andin combination. The first feature is the use of a thermoplastic polymeras an adhesive for the manufacture of tobacco sheet. The second featureis the technique of applying tobacco material which may be eithertobacco or a material derived therefrom on at least one surface of asuspended film. In combination thermally softened plastic film issuspended and tobacco material is applied to the surface of the polymerfilm.

What is claimed is:

l. A method of making tobacco sheet which comprises in combination thesteps of suspending a self-supporting sticky polymer film and applyingfinely divided tobacco material to said film to form a tobacco sheet.

2. A method of making tobacco sheet which comprises in combination thesteps of suspending a self-supporting sticky polymer film, applyingfinely divided tobacco to at least one surface of said film to form atobacco sheet.

3. A method of making tobacco sheet which comprises in combination thesteps of suspending a self-supporting sticky polymer film, applyingfinely divided tobacco material to at least one urface of said film andimbedding said tobacco material within a matrix of said film.

4. A method of making tobacco sheet which comprises in combination thesteps of forming a self-supporting sticky polymer film having fibersdispersed therein, suspending said film and applying finely dividedtobacco to at least one surface of said film to form a tobacco sheet.

5. A method of making tobacco sheet which comprises in combination thesteps of moving a suspended self-supporting sticky polymer film throughfinely divided tobacco material, imbedding said tobacco material withinsaid film to form a sheet and removing loosely adhering tobacco materialfrom said sheet.

6. A method of making tobacco sheet which comprises in combination thesteps of preparing a sticky polymer film by heating said polymer beyondthe softening tcmperature thereof, applying tobacco material to at leastone sticky surface of said film, imbedding said tobacco material withinsaid film and hardening said film to form tobacco sheet.

7. A method of making tobacco sheet which comprises in combination thesteps of suspending a thermally softened, sticky polymer film, coatingsaid film with finely divided tobacco material and hardening said filmwith finely divided tobacco in adhering relationship thereto.

8. A method according to claim 1 wherein the film is cellulosic.

9. A method according to claim 1 wherein the film is a polyolefin.

10. A method of making tobacco sheet which comprises in combination thesteps of adhering together a layer of heat softened adhesive and a layerof finely divided tobacco and forming a sheet therefrom.

11. A method of making a smoking product which comprises in combinationthe steps of softening an adhesive by heating, adhering a layer of saidheat softened adhesive to a layer of finely divided tobacco and coolingsaid adhesive.

References Cited in the file of this patent UNITED STATES PATENTS 61,275Stayman Jan. 15, 1867 1,845,264 Grunauer Feb. 16, 1932 2,309,975 Moseleyet al. Feb. 2, 1943 2,433,877 Wells et al. Jan. 6, 1948 2,483,418 KamletOct. 4, 1949 2,485,670 Sowa et al. Oct. 25, 1949 2,708,175 Samfield etal May 10, 1955 2,734,510 Hungerford et al Feb. 14, 1956 2,747,583Frankenburg et al May 29, 1956

1. A METHOD OF MAKING TOBACCO SHEET WHICH COMPRISES IN COMBINATION THESTEPS OF SUSPENDING A SELF-SUPPORTING STICKY POLYMER FILM AND APPLYINGFINELY DIVIDED TOBACCO MATERIAL TO SAID FILM TO FORM A TOBACCO SHEET.